As is well known, a rotary impact tool includes a drive mechanism that uses rotating mass to store kinetic energy. This rotating mass is momentarily coupled at high velocity to impact the “anvil” or output side of the drive train. The rapid succession of these small impacts results in an intermittent rotation of the anvil. These impacts impart a very high momentary force (i.e., “whack”) on the drive train, and in turn, any other accessory being driven by the tool.
The high power drive mechanism of rotary impact tools make them suitable for driving and remove fasteners, such as bolts or nuts used in machine or automotive applications. Such applications often require specific precise alignment of the fastener for properly threading the fastener into its designated cavity. Misalignment while driving the fastener into a cavity can cause cross threading and or rounding of the fastener's head, leaving an inoperable assembly and a damaged fastener. Therefore, impact tool drive accessories that help to aid and maintain alignment of a fastener such as a bolt or nut have been developed. Such “off-axis” tool drive accessories are suitable for delivery torque to the fastener at an angle offset from the impact tool longitudinal axis. The drive accessories may include a universal joint, ball joint, etc., that couples the fastener to the impact tool and allows the fastener to be driven at an angle from the impact tool.
These off-axis tool accessories have been specifically designed for rotary impact tools, which, as is well known in the art, are powerful but mechanically inefficient, and therefore have been traditionally powered by compressed air. However, improvements in power and motor technology have helped to offset this inefficiency, allowing cordless electric impact tools to gain an increasing presence in the tool market.
Cordless electric impact tools, though suitable for many uses, may be used in applications similar to traditional cordless drills. However, the tool accessories available for traditional (compressed air powered) rotary impact tools have not been designed for cordless tool applications. Moreover, the tool accessories available for traditional cordless drills are typically unsuitable for the high momentary torque loads of a rotary impact tool. As such, there is a need for accessories that are specifically tailored for use with cordless high momentary torque tools, such as cordless impact tools and the like. Such an accessory should allow for off-axis deflection to drive and remove fasteners at an angle offset from the impact tool longitudinal axis.